Document U.S. Pat. No. 7,883,125 discloses latching boxes for selectively holding in position a movable element such as an undercarriage or a hatch, each box comprising a hook mounted to move between an engaged position and a disengaged position relative to the movable element, a locking member that is movable between a position for blocking the hook in the engaged position and a release position for releasing the hook, and two actuators, including a cam actuator in which the cam co-operates with the locking member in order to move it towards the release position.
In that document, the hook, the locking member, and the cam are all mounted to pivot about axes that are parallel. The use of a rotary cam serves to simplify the control of the actuator, since the actuator can be reset by causing the cam to rotate through one complete revolution. Thus, in order to control the actuator, it suffices to switch on its motor until a position sensor indicates that one complete revolution has been performed.
Nevertheless, in those arrangements, the emergency actuator with a cam projects from one of the faces of the box and thus increases its overall size considerably.